Bug #73298 [NEW]: DateTime::add adding 1 month on 31st of August skips to October

From: enachesilviu at live dot com Operating system: CentOS 6 PHP version: Irrelevant Package: Date/time related Bug Type: Bug Bug description:DateTime::add adding 1 month on 31st of August skips to October Description: ------------ DateTime::add adding 1 month on 31st of August skips to October I did a similar snippet in Java and I get the expected result: import java.util.*; import java.text.*; import java.lang.*; class TestingDateTime { public static void main (String[] args) throws java.lang.Exception { SimpleDateFormat ft = new SimpleDateFormat ("yyyy-MM-dd"); Date date = ft.parse("2016-08-31"); System.out.println("Initial value:"); System.out.println(ft.format(date)); Calendar calendar = Calendar.getInstance(); calendar.setTime(date); calendar.add(Calendar.MONTH, 1); date = calendar.getTime(); System.out.println("\nNew value:"); System.out.println(ft.format(date)); } } Test script: --------------- <?php function printline($value) { $separator = 'cli' == php_sapi_name() ? PHP_EOL : '<br/>'; echo $value . $separator; } $dateTime = new DateTime('2016-08-31 00:00:00'); printline('Initial value: ' . $dateTime->format('Y-m-d H:i:s')); $dateTime->add(new DateInterval('P1M')); printline('New value: ' . $dateTime->format('Y-m-d H:i:s')); Expected result: ---------------- 2016-09-30 00:00:00 Actual result: -------------- 2016-10-01 00:00:00 -- Edit bug report at https://bugs.php.net/bug.php?id=73298&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=73298&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=73298&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=73298&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=73298&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=73298&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=73298&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=73298&r=needscript Try newer version: https://bugs.php.net/fix.php?id=73298&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=73298&r=support Expected behavior: https://bugs.php.net/fix.php?id=73298&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=73298&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=73298&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=73298&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=73298&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=73298&r=dst IIS Stability: https://bugs.php.net/fix.php?id=73298&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=73298&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=73298&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=73298&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=73298&r=mysqlcfg